CN212343374U - Protection circuit of variable voltage lithium cell group - Google Patents
Protection circuit of variable voltage lithium cell group Download PDFInfo
- Publication number
- CN212343374U CN212343374U CN202021235351.8U CN202021235351U CN212343374U CN 212343374 U CN212343374 U CN 212343374U CN 202021235351 U CN202021235351 U CN 202021235351U CN 212343374 U CN212343374 U CN 212343374U
- Authority
- CN
- China
- Prior art keywords
- circuit
- battery pack
- signal
- detection processing
- processing circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Secondary Cells (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
A protection circuit of a variable voltage lithium battery pack comprises a first battery pack; first RC filtering; a first signal detection processing circuit; a second battery pack; second RC filtering; a second signal detection processing circuit; the method is characterized in that: the bidirectional isolating circuit is also included; an input/output interface circuit. The utility model has the advantages that: on the premise of not changing the existing charge-discharge interface, two lithium battery packs and protection circuits thereof in the pack are charged respectively by controlling the positive electrodes in common during charging, and whether the two lithium battery packs and the protection circuits thereof work in a series connection state or a parallel connection state is determined by an external connection mode during discharging, so that the use is flexible and convenient; the variable voltage output of the battery pack is realized, and the application range of the battery pack is greatly widened.
Description
Technical Field
The utility model relates to a lithium battery protection circuit especially relates to a protection circuit of variable voltage lithium cell group.
Background
Overcharge, overdischarge, over-temperature or over-current of a lithium battery may affect the service life of the battery, and particularly, overcharge may easily cause explosion. In order to take safety into consideration, a protection board is additionally arranged in a charging and discharging circuit of a lithium battery, and strict requirements are required for the design of the charging and protecting circuit of the lithium battery in the industry.
As shown in fig. 1, for filtering an interference signal, an RC filter circuit 2 'is usually connected between a lithium battery pack 1' and a signal detection processing circuit 3 'to filter the interference signal, when charging, a charger wakes up the lithium battery protection circuit through an ID port, the signal detection processing circuit 3' monitors data such as cell voltage and battery pack temperature of each section (more than two lithium batteries are connected in parallel and also count as one lithium battery), when all the cell voltages are not overcharged and other charging conditions are met, the signal detection processing circuit 3 'outputs a charging permission signal to the ID port through an input/output interface circuit 4', and the charger continues to charge; otherwise, when any power saving core is overcharged or other charging conditions are not met, the signal detection processing circuit 3 'outputs a charging prohibition signal to the ID end through the input/output interface circuit 4', and the charger stops charging; when discharging, the discharging control circuit wakes up the lithium battery protection circuit through an ID port (or additionally provided with a port), the signal detection processing circuit 3 ' monitors data such as voltage of each electricity-saving core, temperature of a battery pack and the like in real time, when all the electricity-saving cores are not over-discharged and other discharging conditions are met, the signal detection processing circuit 3 ' outputs a discharging-allowing signal to the ID port through the input and output interface circuit 4 ', and the discharging control circuit continues discharging; on the contrary, when any electricity-saving core is overdischarged or other discharge conditions are not met, the signal detection processing circuit 3 'outputs a discharge inhibiting signal to the ID end through the input/output interface circuit 4', and the discharge control circuit stops discharging.
In practical application, for convenience of use, application of dual voltages is increasingly popular, that is, one battery pack comprises two lithium battery packs and protection circuits thereof, which are externally presented as two positive output terminals and two negative output terminals, and when charging, two groups of lithium batteries and protection circuits thereof are respectively charged in a positive controlled manner together; during discharging, whether the two groups of lithium batteries work in a series connection state or a parallel connection state is determined by an external connection mode. At present, in consideration of cost and compatibility of front and rear interfaces of new and old battery packs, for a protection circuit of a dual-voltage battery pack, generally, the number of ports corresponding to an input/output interface circuit in the protection circuit cannot be increased at will, and two signal detection circuits of two lithium battery packs in the dual-voltage battery pack have coordination work such as parameter distribution, data transmission processing and the like, and the two signal detection processing circuits have the condition of sometimes being common and sometimes not being common, so that difficulty is brought to circuit design, the circuit structure in the existing design is complex, and the design and manufacturing cost is high.
In addition, considering that the existing old battery pack with single-voltage output has some solidified designs, for example, the discharge protection execution circuit is integrated into the lithium battery protection circuit, the discharge protection execution circuit itself is an existing functional module, and includes a power switch circuit 5 ', a follow current circuit 6 ' and a load detection circuit 7 ', as shown in fig. 4, in this case, if the two old battery packs with single-voltage output are directly combined to realize double-voltage output, components in the original follow current circuit may be over-current damaged when the two old battery packs are connected in series for operation, and the traditional follow current circuit connection method is not applicable; during discharge control, the signal detection processing circuit cannot identify the series-parallel connection state of the battery voltage corresponding to the external equipment, so that a corresponding protection strategy cannot be performed on the battery pack. Therefore, in order to continue to use the old battery pack in the prior art in the new battery pack with dual voltage outputs and ensure the reliable operation of each component in the new circuit, the protection circuit of the new battery pack needs to be redesigned and improved to meet the safety requirement of the circuit with dual voltage outputs and simultaneously take into account the compatible use of the old battery pack.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the first technical problem that to above-mentioned prior art current situation and provide a protection circuit of variable voltage lithium cell group that circuit structure is simple and compatible good.
The utility model aims to solve the second technical problem that to above-mentioned prior art current situation and provide a protection circuit that can prevent that follow current components and parts from damaging and the high vary voltage lithium cell group of operational reliability.
The utility model aims to solve the third technical problem that to above-mentioned prior art current situation and provide a protection circuit of series-parallel connection operating voltage's that can effectively discern external load corresponds variable voltage lithium cell group.
The utility model provides a technical scheme that above-mentioned first technical problem adopted does: a protection circuit of a variable voltage lithium battery pack comprises
The first battery pack comprises at least two lithium batteries which are connected in series;
the first RC filter comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the first battery pack in series;
the first signal detection processing circuit comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the first RC filter is connected to the corresponding detection signal input end of the first signal detection processing circuit;
the second battery pack comprises at least two lithium batteries which are connected in series;
the second RC filter comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the second battery pack in series;
the second signal detection processing circuit comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the second RC filter is connected to the corresponding detection signal input end of the second signal detection processing circuit;
the method is characterized in that: the protection circuit also comprises
The bidirectional isolation circuit can realize bidirectional communication and signal isolation between the first signal detection processing circuit and the second signal detection processing circuit, and comprises a first signal transmission end and a second signal transmission end;
the input/output interface circuit comprises a first signal end and a second signal end which can realize bidirectional communication, and is used for realizing signal transmission between the battery pack and the charger and between the battery pack and the discharge controller;
the first signal detection processing circuit comprises a first communication end and a second communication end, the second signal detection processing circuit comprises a third communication end, a first signal transmission end of the bidirectional isolation circuit is connected with the first communication end, a second signal transmission end of the bidirectional isolation circuit is connected with the third communication end, a first signal end of the input/output interface circuit is connected with a second communication end of the first signal detection processing circuit, and a second signal end of the input/output interface circuit is connected to an input end of the charger circuit or the discharge controller as a total output end.
In order to simplify the circuit structure, preferably, the bidirectional isolation circuit may use an optocoupler as a core, and specifically includes a first optocoupler, a second optocoupler, a first resistor and a second resistor, the first communication terminal includes a first output communication terminal and a first input communication terminal, and the third communication terminal includes a third output communication terminal and a third input communication terminal; the positive electrode of the light emitting diode of the first optocoupler is connected with a first output communication end, the negative electrode of the light emitting diode of the first optocoupler is connected with the negative electrode of the first battery pack through a first resistor, the collector electrode of the triode of the first optocoupler is connected with a third input communication end, and the emitter electrode of the triode of the first optocoupler is connected with the negative electrode of the second battery pack; the positive electrode of the light emitting diode of the second optocoupler is connected with the third output communication end, the negative electrode of the light emitting diode of the second optocoupler is connected with the negative electrode of the second battery pack through a second resistor, the collector electrode of the triode of the second optocoupler is connected with the first input communication end, and the emitter electrode of the triode of the second optocoupler is connected with the negative electrode of the first battery pack.
Preferably, the first signal detection processing circuit and the second signal detection processing circuit can be implemented by various chips in the prior art, and preferably, an integrated circuit with a model of BigSur6 is selected.
The utility model provides a technical scheme that above-mentioned second and third technical problem adopted is: a protection circuit of a variable voltage lithium battery pack comprises
The first battery pack comprises at least two lithium batteries which are connected in series;
the first RC filter comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the first battery pack in series;
the first signal detection processing circuit comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the first RC filter is connected to the corresponding detection signal input end of the first signal detection processing circuit;
the second battery pack comprises at least two lithium batteries which are connected in series;
the second RC filter comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the second battery pack in series;
the second signal detection processing circuit comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the second RC filter is connected to the corresponding detection signal input end of the second signal detection processing circuit;
the method is characterized in that: the protection circuit also comprises
The bidirectional isolation circuit can realize bidirectional communication and signal isolation between the first signal detection processing circuit and the second signal detection processing circuit, and comprises a first signal transmission end and a second signal transmission end;
the input/output interface circuit comprises a first signal end and a second signal end which can realize bidirectional communication, and is used for realizing signal transmission between the battery pack and the charger and between the battery pack and the discharge controller;
the first power switch circuit and the second power switch circuit are used for controlling the on and off of an external discharge controller circuit when the first battery pack and the second battery pack are in different series-parallel connection states;
the follow current circuit provides a current loop for the reverse electromotive force generated by the inductive load at the moment of switching off the power switch circuit;
the series-parallel detection circuit is used for detecting the series-parallel working state of the external load on the protection circuit;
the load detection circuit is used for detecting whether an external load is connected to the protection circuit and sending a trigger signal to the first signal detection processing circuit; the first signal detection processing circuit comprises a first communication end, a second communication end, a third communication end, a fourth communication end and a fifth communication end, and the second signal detection processing circuit comprises a sixth communication end and a seventh communication end;
a first signal end of the input/output interface circuit is connected with a fifth communication end of the first signal detection processing circuit, and a second signal end of the input/output interface circuit is used as a total output end and is connected to an input end of the charger circuit or the discharge controller;
the first signal transmission end of the bidirectional isolation circuit is connected with the first communication end of the first signal detection processing circuit, and the second signal transmission end of the bidirectional isolation circuit is connected with the sixth communication end of the second signal detection processing circuit;
the second communication end of the first signal detection processing circuit is connected with the series-parallel detection circuit; the third communication end of the first signal detection processing circuit is connected with the input end of the first power switch circuit, the output end of the first power switch circuit is used as the first negative electrode discharge output end of the whole protection circuit, and the positive electrode of the first battery pack is used as the first positive electrode discharge output end of the whole protection circuit; the fourth communication end of the first signal detection processing circuit is connected with the output end of the load detection circuit, and the input end of the load detection circuit is connected with the first negative electrode discharge output end;
a seventh communication end of the second signal detection processing circuit is connected with an input end of a second power switch circuit, an output end of the second power switch circuit is used as a second negative electrode discharge output end of the whole protection circuit, and a positive electrode of a second battery pack is used as a second positive electrode discharge output end of the whole protection circuit;
and the follow current circuit is also connected in series between the second positive electrode discharge output end and the first negative electrode discharge output end.
Preferably, the bidirectional isolation circuit comprises a first optocoupler, a second optocoupler, a first resistor and a second resistor, the first communication terminal comprises a first output communication terminal and a first input communication terminal, and the sixth communication terminal comprises a sixth output communication terminal and a sixth input communication terminal; the positive electrode of the light emitting diode of the first optocoupler is connected with a first output communication end, the negative electrode of the light emitting diode of the first optocoupler is connected with the negative electrode of the first battery pack through a first resistor, the collector electrode of the triode of the first optocoupler is connected with a sixth input communication end, and the emitter electrode of the triode of the first optocoupler is connected with the negative electrode of the second battery pack; the positive electrode of the light emitting diode of the second optocoupler is connected with the sixth output communication end, the negative electrode of the light emitting diode of the second optocoupler is connected with the negative electrode of the second battery pack through a second resistor, the collector electrode of the triode of the second optocoupler is connected with the first input communication end, and the emitter electrode of the triode of the second optocoupler is connected with the negative electrode of the first battery pack. The double-optical coupling isolation circuit is simple in structure and easy to realize, signal isolation between the two signal detection processing circuits can be realized, and bidirectional communication between the two signal detection processing circuits can also be realized.
Preferably, the first signal detection processing circuit and the second signal detection processing circuit are integrated circuits of the type BigSur6 respectively.
In order to ensure reliable follow current when the first battery pack and the second battery pack are used in series or in parallel, the follow current circuit preferably comprises a follow current diode, the anode of the follow current diode is connected with the first cathode discharge output end, and the cathode of the follow current diode is connected with the second anode discharge output end.
Because the discharge protection execution circuit is integrated in the lithium battery protection circuit, after a load is accessed, the battery pack needs to know whether the current access is a load for connecting two battery packs in series or a load for connecting the two battery packs in parallel so as to distribute working parameters and relevant data processing, and in order to detect the working voltage of an external load (namely the serial-parallel connection use state of the two battery packs), the serial-parallel connection detection circuit is preferably simple and can adopt the following circuit structure, the serial-parallel connection detection circuit comprises a digital triode, the collector of the digital triode is connected with the second communication end of the first signal detection processing circuit pack, the emitter of the digital triode is connected with the negative electrode of the first battery pack, and the base of the digital triode is connected with the negative electrode of the second battery pack.
Compared with the prior art, the utility model has the advantages of: on the premise of not changing the existing charge-discharge interface, one battery pack comprises two lithium battery packs, two positive electrodes and two negative electrode output terminals are externally presented, the two lithium battery packs are awakened and communicated through a bidirectional isolating circuit, the protection function is reliable, and the circuit structure is simple; during charging, the two lithium battery packs and the protection circuits thereof in the pack are charged by controlling the anodes of the two lithium battery packs and the protection circuits thereof in common, and during discharging, the two lithium battery packs and the protection circuits thereof are determined to work in a serial state or a parallel state by an external connection mode, so that the use is flexible and convenient; the battery pack of this embodiment can realize two kinds of operating voltage's output under two lithium cell group series connection or parallelly connected different states, has realized the variable voltage output of battery pack, has widened the range of application of battery pack greatly, can be compatible current single voltage output's old battery pack simultaneously, and the practicality is strong.
Drawings
Fig. 1 is a schematic diagram of a lithium battery pack protection circuit (no discharge protection circuit) according to the prior art.
Fig. 2 is a schematic diagram of a working principle of a protection circuit of a variable voltage lithium battery pack according to a first embodiment of the present invention.
Fig. 3 is a specific circuit diagram of the bidirectional isolation circuit and the input/output interface circuit according to the first embodiment of the present invention.
Fig. 4 is a second schematic diagram (including a discharge protection circuit) of a lithium battery pack protection circuit in the prior art.
Fig. 5 is a working schematic diagram of a variable voltage lithium battery pack protection circuit according to an embodiment of the present invention.
Fig. 6 is a specific circuit diagram of the bidirectional isolation circuit, the input/output interface circuit, the series/parallel detection circuit, the freewheel circuit, the load detection circuit, and the power switch circuit in the second embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
In the first embodiment, as shown in fig. 2 and 3:
the embodiment discloses a protection circuit of a variable voltage lithium battery pack, which comprises
A first battery pack 1 including at least two lithium batteries connected in series with each other;
the first RC filter 2 comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the first battery pack 1 in series;
the first signal detection processing circuit 3 comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the first RC filter 2 is connected to the corresponding detection signal input end of the first signal detection processing circuit 3;
a second battery pack 5 including at least two lithium batteries connected in series with each other;
the second RC filter 6 comprises a plurality of RC filter circuits which are correspondingly connected in series with each lithium battery in the second battery pack 5;
a second signal detection processing circuit 7, which comprises a plurality of detection signal input terminals and at least one communication terminal, wherein the output terminal of each RC filter circuit in the second RC filter 6 is connected to the corresponding detection signal input terminal of the second signal detection processing circuit 7;
a bidirectional isolation circuit 8 for implementing bidirectional communication and signal isolation between the first signal detection processing circuit 3 and the second signal detection processing circuit 7, wherein the bidirectional isolation circuit 8 comprises a first signal transmission terminal 81 and a second signal transmission terminal 82;
the input/output interface circuit 4 includes a first signal terminal 4a and a second signal terminal 4b capable of realizing bidirectional communication, and the input/output interface circuit 4 is used for realizing signal transmission between the battery pack and the charger and between the battery pack and the discharge controller.
The first signal detection processing circuit 3 includes a first communication terminal 31 and a second communication terminal 32, the second signal detection processing circuit 7 includes a third communication terminal 71, the first communication terminal 31 of the first signal detection processing circuit 3 includes a first output communication terminal 311 and a first input communication terminal 312, the second communication terminal 32 of the first signal detection processing circuit 3 includes a second output communication terminal 321 and a second input communication terminal 322, and the third communication terminal 71 of the second signal detection processing circuit 7 includes a third input communication terminal 711 and a third output communication terminal 712;
the first signal transmission terminal 81 of the bidirectional isolation circuit 8 is connected to the first communication terminal 31 of the first signal detection processing circuit 3, the second signal transmission terminal 82 of the bidirectional isolation circuit 8 is connected to the third communication terminal 71 of the second signal detection processing circuit 7, the input/output interface circuit 4 includes two signal terminals capable of bidirectional communication, the first signal terminal 4a of the input/output interface circuit 4 is connected to the second communication terminal 32 of the first signal detection processing circuit 3, the second signal terminal 4b of the input/output interface circuit 4 is connected to the input terminal of the charger circuit or the discharge controller as the total output terminal ID, and the input/output interface circuit 4 is disposed between the first signal detection processing circuit 3 and the total output terminal ID.
In the above circuit module, the first RC filter 2, the second RC filter 6, the first signal detection processing circuit 3, and the second signal detection processing circuit 7 are all the prior art, and can be implemented by using the corresponding circuit structures in the prior art, and preferably, the first signal detection processing circuit 3 and the second signal detection processing circuit 7 are the integrated circuit U1 and the integrated circuit U2 of BigSur6, respectively.
For the protection circuit of the dual-voltage battery pack, generally, it is required that the number of ports corresponding to the input/output interface circuit 4 in the protection circuit cannot be increased at will, the number of ports corresponding to the input/output interface circuit 4 under the original condition of a single battery pack is two, the protection circuit of the dual-voltage battery pack is adopted at present, only one input/output interface circuit 4 is reserved, the number of corresponding ports is still two, the input/output interface circuit 4 herein can be realized by adopting a circuit structure in the prior art, and the following circuit structure is specifically adopted in this embodiment: the input/output interface circuit 4 comprises a first triode Q1 and a second triode Q2, wherein the collector of the first triode Q1 is connected with the second input communication terminal 322, and the emitter of the first triode Q1 is connected with the cathode of the first battery pack 1; the base of the second triode Q2 is connected to the second output communication terminal 321, the emitter of the second triode Q2 is connected to the negative electrode of the first battery pack 1, and the collector of the second triode Q2 is connected to the base of the first triode Q1 and then connected to the input terminal of the charger circuit or the discharge controller as the total output terminal ID.
The core device of the bidirectional isolation circuit 8 may be an optical isolation device, a magnetic isolation device, and an isolation device based on a capacitor, the bidirectional isolation circuit 8 of this embodiment adopts an optical coupler structure, specifically, the bidirectional isolation circuit 8 includes a first optical coupler U3, a second optical coupler U4, a first resistor R1, and a second resistor R2, the anode of the light emitting diode of the first optical coupler U3 is connected to the first output communication terminal 311, the cathode of the light emitting diode of the first optical coupler U3 is connected to the cathode of the first battery pack 1 through the first resistor R1, the collector of the triode of the first optical coupler U3 is connected to the third input communication terminal 711, and the emitter of the triode of the first optical coupler U3 is connected to the cathode of the second battery pack 5; the anode of the light emitting diode of the second optocoupler U4 is connected with the third output communication terminal 712, the cathode of the light emitting diode of the second optocoupler U4 is connected with the cathode of the second battery pack 5 through a second resistor R2, the collector of the triode of the second optocoupler U4 is connected with the first input communication terminal 312, and the emitter of the triode of the second optocoupler U4 is connected with the cathode of the first battery pack 1.
The basic working principle of the first embodiment is as follows:
when the charger or the discharge controller is not connected with the dual-voltage battery pack or is connected with the dual-voltage battery pack and does not work, the ID port of the total output end does not present an effective voltage signal, at the moment, the first triode Q1 is cut off, the collector of the first triode Q1 keeps a high level, the first signal detection processing circuit 3 is still in a dormant state, and the second signal detection processing circuit 7 is also in a dormant state; when the charger or the discharge controller is connected and starts to work, the ID port of the total output end presents an effective voltage signal, at this time, the first triode Q1 is turned on, the second input communication end 322 of the first signal detection processing circuit 3 receives a signal that the collector of the first triode Q1 changes from high to low, the first signal detection processing circuit 3 is awakened, the first signal detection processing circuit 3 then awakens the second signal detection processing circuit 7 through the first optical coupler U3, and at the same time, the first signal detection processing circuit 3 controls the second triode Q2 to send a signal to the charger or the discharge controller through the second output communication end 321.
When the charger or the discharge controller disconnects the master output terminal ID or still connects the master output terminal ID but stops working, at this time, the first transistor Q1 is turned off, the collector of the first transistor Q1 keeps at a high level, the first signal detection processing circuit 3 notifies the second signal detection processing circuit 7 to enter the sleep state through the first optocoupler U3, and then the first signal detection processing circuit 3 itself also enters the sleep state.
In the charging and discharging working process, the second signal detection processing circuit 7 also monitors whether the charging and discharging conditions are met in real time, if not, the second signal detection processing circuit 7 sends a signal to the first signal detection processing circuit 3 through the second optocoupler U4, and after receiving the charging and discharging prohibition signal, the first signal detection processing circuit 3 stops charging and discharging and then enters the dormancy state.
This embodiment can awaken up second signal detection processing circuit 7 through first signal detection processing circuit 3 when the charger is connected to the battery package or the controller that discharges through setting up two-way isolating circuit 8, and then realizes the series-parallel connection work of two group batteries, and simultaneously, second signal detection processing circuit 7 can export feedback signal through two-way isolating circuit 8 again to stop charging under the condition that the battery package is full of electricity, perhaps stop discharging under the condition that the battery package electric quantity is not enough.
Example two, as shown in fig. 5 and 6:
the difference between this embodiment and the first embodiment is that the discharge protection execution circuit is integrated into the lithium battery protection circuit in this embodiment, and in order to ensure reliable operation and safe use of the circuit, when a dual-voltage battery pack is implemented, the protection circuits of two single battery packs respectively having the discharge protection execution circuit cannot be directly and simply combined, and some improvements and adjustments need to be made.
The protection circuit of the variable voltage lithium battery pack of the embodiment comprises:
a first battery pack 1 including at least two lithium batteries connected in series with each other;
the first RC filter 2 comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the first battery pack 1 in series;
the first signal detection processing circuit 3 comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the first RC filter 2 is connected to the corresponding detection signal input end of the first signal detection processing circuit 3;
a second battery pack 5 including at least two lithium batteries connected in series with each other;
the second RC filter 6 comprises a plurality of RC filter circuits which are correspondingly connected in series with each lithium battery in the second battery pack 5;
and the second signal detection processing circuit 7 comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the second RC filter 6 is connected to the corresponding detection signal input end of the second signal detection processing circuit 7.
The protection circuit of the present embodiment further includes:
a bidirectional isolation circuit 8 for implementing bidirectional communication and signal isolation between the first signal detection processing circuit 3 and the second signal detection processing circuit 7, wherein the bidirectional isolation circuit 8 comprises a first signal transmission terminal 81 and a second signal transmission terminal 82;
the input/output interface circuit 4 comprises a first signal end 4a and a second signal end 4b which can realize bidirectional communication, and the input/output interface circuit 4 is used for realizing signal transmission between the battery pack and the charger and between the battery pack and the discharge controller;
the first power switch circuit 41 and the second power switch circuit 42 are used for controlling the on and off of an external load circuit when the first battery pack 1 and the second battery pack 5 are in different series-parallel connection states;
a freewheel circuit 43 that provides a current loop for the back electromotive force generated by the inductive load at the moment when the power switch circuit is turned off; when current passes through an inductive load (such as a coil), induced electromotive force is generated at two ends of the inductive load, when the current disappears, the induced electromotive force of the inductive load can generate reverse voltage for elements in a circuit, and when the reverse voltage is higher than the reverse breakdown voltage of the elements, the elements such as a triode, a thyristor and the like can be damaged. Therefore, it is usually necessary to connect the freewheeling diode Dx in reverse parallel at two ends of the inductive load, and when the current flowing through the inductive load (such as the coil) disappears, the induced electromotive force generated by the inductive load is consumed by the work of the loop formed by the diode and the coil, thereby protecting the safety of other components in the circuit;
the series-parallel detection circuit 9 is used for detecting the series-parallel working state of the external load on the protection circuit;
the load detection circuit 44 is configured to detect whether an external load is connected to the protection circuit and send a trigger signal to the first signal detection processing circuit 3, where the first signal detection processing circuit 3 includes a first communication terminal 31, a second communication terminal 32, a third communication terminal 33, a fourth communication terminal 34, and a fifth communication terminal 35, and the second signal detection processing circuit 7 includes a sixth communication terminal 71 and a seventh communication terminal 72;
the first signal end 4a of the input/output interface circuit 4 is connected with the fifth communication end 35 of the first signal detection processing circuit 3, and the second signal end 4b of the input/output interface circuit 4 is used as a total output end ID to be connected to the input end of the charger circuit or the discharge controller;
the first signal transmission terminal 81 of the bidirectional isolation circuit 8 is connected to the first communication terminal 31 of the first signal detection processing circuit 3, and the second signal transmission terminal 82 of the bidirectional isolation circuit 8 is connected to the sixth communication terminal 71 of the second signal detection processing circuit 7;
the second communication terminal 32 of the first signal detection processing circuit 3 is connected with the series-parallel detection circuit 9; the third communication terminal 33 of the first signal detection processing circuit 3 is connected to the input terminal of the first power switch circuit 41, the output terminal of the first power switch circuit 41 serves as the first negative discharge output terminal P1 "of the whole protection circuit, and the positive electrode of the first battery pack 1 serves as the first positive discharge output terminal P1+ of the whole protection circuit; the fourth communication terminal 34 of the first signal detection processing circuit 3 is connected to the output terminal of the load detection circuit 44, and the input terminal of the load detection circuit 44 is connected to the first negative discharge output terminal P1-;
the seventh communication terminal 72 of the second signal detection processing circuit 7 is connected to the input terminal of the second power switch circuit 42, the output terminal of the second power switch circuit 42 serves as the second negative discharge output terminal P2 "of the whole protection circuit, and the positive terminal of the second battery pack 5 serves as the second positive discharge output terminal P2+ of the whole protection circuit;
a freewheeling circuit 43 is connected in series between the second positive discharging output terminal P2+ and the first negative discharging output terminal P1-.
In the embodiment, the first negative discharge output end P1-, the first positive discharge output end P1+, the second negative discharge output end P2-and the second positive discharge output end P2+ are four reserved electrode interface ends, when an external load is applied in series, the second negative discharge output end P2-and the first positive discharge output end P1+ are short-circuited externally, the first negative discharge output end P1-is a total negative electrode of the whole battery pack, and the second positive discharge output end P2+ is a total positive electrode of the whole battery pack; when the external loads are applied in parallel, the first positive electrode discharge output end P1+ and the second positive electrode discharge output end P2+ are externally short-circuited to serve as the total positive electrode of the whole battery pack, and the first negative electrode discharge output end P1-and the second negative electrode discharge output end P2-are externally short-circuited to serve as the total negative electrode of the whole battery pack.
In the above circuit module, the first RC filter 2, the second RC filter 6, the first signal detection processing circuit 3, and the second signal detection processing circuit 7 are all the prior art, and can be implemented by using the corresponding circuit structures in the prior art, and preferably, the first signal detection processing circuit 3 and the second signal detection processing circuit 7 are the integrated circuit U1 and the integrated circuit U2 of BigSur6, respectively.
The first power switch circuit 41, the second power switch circuit 42, the load detection circuit 44 and the freewheel circuit 43 are generated by integrating a discharge protection execution circuit in a battery pack protection circuit, and the circuit structures of the first power switch circuit 41, the second power switch circuit 42, the load detection circuit 44 and the freewheel circuit 43 are all the prior art, and can be implemented by adopting various circuit structures in the prior art, and preferably, the function modules related to the discharge protection execution circuit are implemented by the following specific circuit structures:
the first power switch circuit 41 includes a first fet Qa, the second power switch circuit 42 includes a second fet Qb, the freewheel circuit 43 includes a freewheel diode Dx, and the load detection circuit 44 includes a first diode D1 and a third resistor R3;
the anode of the freewheeling diode Dx is connected with the first cathode discharge output end P1-, and the cathode of the freewheeling diode Dx is connected with the second anode discharge output end P2 +; whether the two battery packs are connected in parallel or in parallel, the first negative electrode discharge output end P1-can always represent the total negative electrode output by the battery pack, the second positive electrode discharge output end P2+ can always represent the total positive electrode output by the battery pack, and the freewheeling diode Dx is connected in such a way, so that the reverse electromotive force generated by the inductive load in the circuit at the moment of turning off the power switch circuit can be eliminated, and components in the circuit are protected; the grid of the first field effect transistor Qa is connected to the third communication terminal 33 of the first signal detection processing circuit 3, the drain of the first field effect transistor Qa is connected to the first negative discharge output terminal P1-, and the source of the first field effect transistor Qa is connected to the negative electrode of the first battery pack 1; the grid electrode of the second field effect tube Qb is connected with the seventh communication terminal 72 of the second signal detection processing circuit 7, the drain electrode of the second field effect tube Qb is connected with the second negative electrode discharge output terminal P2-, and the source electrode of the second field effect tube Qb is connected with the negative electrode of the second battery pack 5; the anode of the first diode D1 is connected to the first cathode discharge output terminal P1-, and the cathode of the first diode D1 is connected to the fourth communication terminal 34 of the first signal detection processing circuit 3 via the third resistor R3.
The core device of the bidirectional isolation circuit 8 may be an optical isolation, a magnetic isolation, and a capacitor-based isolation device, the bidirectional isolation circuit 8 of this embodiment includes a first optical coupler U3, a second optical coupler U4, a first resistor R1, and a second resistor R2, the first communication terminal 31 includes a first output communication terminal 311 and a first input communication terminal 312, and the sixth communication terminal 71 includes a sixth input communication terminal 711 and a sixth output communication terminal 712;
the anode of a light emitting diode of the first optocoupler U3 is connected with the first output communication end 311, the cathode of the light emitting diode of the first optocoupler U3 is connected with the cathode of the first battery pack 1 through a first resistor R1, the collector of a triode of the first optocoupler U3 is connected with the sixth input communication end 711, and the emitter of the triode of the first optocoupler U3 is connected with the cathode of the second battery pack 5;
the positive electrode of a light emitting diode of the second optocoupler U4 is connected with the sixth output communication end 712, the negative electrode of the light emitting diode of the second optocoupler U4 is connected with the negative electrode of the second battery pack 5 through a second resistor R2, the collector electrode of a triode of the second optocoupler U4 is connected with the first input communication end 312, and the emitter electrode of the triode of the second optocoupler U4 is connected with the negative electrode of the first battery pack 1.
The series-parallel detection circuit 9 comprises a digital triode Q3, a common triode needs to be additionally provided with a bias resistor, and the digital triode Q3 is internally provided with the bias resistor, so that the circuit structure can be simplified; the collector of the digital triode Q3 is connected to the second communication terminal 32 of the first signal detection processing circuit 3, the emitter of the digital triode Q3 is connected to the cathode of the first battery pack 1, and the base of the digital triode Q3 is connected to the cathode of the second battery pack 5.
The second embodiment has the working principle that:
after the protection circuit of this embodiment is connected to a load (during discharging), it needs to know as soon as possible whether the current access is a load in which two battery packs are used in series or a load in which two battery packs are used in parallel to distribute working parameters and related data processing, and here, the series-parallel connection application for the external load is mainly realized by the series-parallel connection detection circuit 9.
As shown in fig. 6, if the external load is applied in parallel, that is, the first negative discharge output terminal P1-and the second negative discharge output terminal P2-are short-circuited externally, the negative electrode of the first battery pack 1 is connected to the first negative discharge output terminal P1 through the conducting first fet Qa, the negative electrode of the second battery pack 5 is connected to the second negative discharge output terminal P2 through the conducting second fet Qb, at this time, the negative electrode of the first battery pack 1 and the negative electrode of the second battery pack 5 are at the same potential, the digital triode Q3 is turned off, and the second communication terminal 32 of the first signal detection processing circuit 3 connected to the collector of the digital triode Q3 obtains a high level (there is a pull-up inside).
If the external load is applied in series, the second negative electrode discharge output end P2-and the first positive electrode discharge output end P1+ are short-circuited externally, the second positive electrode discharge output end P2+ is the total output positive electrode of the whole battery pack, the first negative electrode discharge output end P1-is the total output negative electrode of the whole battery pack, the negative electrode B2-of the second battery pack 5-is connected to the second negative electrode discharge output end P2- (i.e. the first positive electrode discharge output end P1+) through the conducted second field effect transistor Qb, at this time, the base of the digital triode Q3 is connected to the positive electrode of the first battery pack 1, the emitter of the digital triode Q3 is connected to the negative electrode of the first battery pack 1, the digital triode Q3 is conducted, and the second communication end 32 of the first signal detection processing circuit 3 connected to the collector of the digital triode Q3 obtains a low level.
It can be seen that the high-low level obtained by the second communication terminal 32 of the first signal detection processing circuit 3 can determine whether the external load is applied in series or in parallel.
The first signal terminal and the second signal terminal of the input/output interface circuit 4 in this embodiment are signal terminals capable of achieving bidirectional communication, and the specific circuit structure and implementation principle of the input/output interface circuit 4 are the same as those in the first embodiment, and are not described herein again.
In addition, the working principle of the bidirectional isolation circuit 8 in this embodiment is also the same as that in the first embodiment, and is not described herein again.
Claims (8)
1. A protection circuit of a variable voltage lithium battery pack comprises
A first battery pack (1) comprising at least two lithium batteries connected in series with each other;
the first RC filter (2) comprises a plurality of RC filter circuits which are correspondingly connected in series with each lithium battery in the first battery pack (1);
the first signal detection processing circuit (3) comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the first RC filter (2) is connected to the detection signal input end corresponding to the first signal detection processing circuit (3);
a second battery pack (5) comprising at least two lithium batteries connected in series with each other;
the second RC filter (6) comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the second battery pack (5) in series;
a second signal detection processing circuit (7) comprising a plurality of detection signal input terminals and at least one communication terminal, wherein the output terminal of each RC filter circuit in the second RC filter (6) is connected to the corresponding detection signal input terminal of the second signal detection processing circuit (7);
the method is characterized in that: the protection circuit also comprises
The bidirectional isolation circuit (8) can realize bidirectional communication and signal isolation between the first signal detection processing circuit (3) and the second signal detection processing circuit (7), and the bidirectional isolation circuit (8) comprises a first signal transmission terminal (81) and a second signal transmission terminal (82);
the input/output interface circuit (4) comprises a first signal end (4a) and a second signal end (4b) which can realize bidirectional communication, and the input/output interface circuit (4) is used for realizing signal transmission between the battery pack and the charger and between the battery pack and the discharge controller;
the first signal detection processing circuit (3) comprises a first communication end (31) and a second communication end (32), the second signal detection processing circuit (7) comprises a third communication end (71), a first signal transmission end (81) of the bidirectional isolation circuit (8) is connected with the first communication end (31) of the first signal detection processing circuit (3), a second signal transmission end (82) of the bidirectional isolation circuit (8) is connected with the third communication end (71) of the second signal detection processing circuit (7), a first signal end (4a) of the input/output interface circuit (4) is connected with the second communication end (32) of the first signal detection processing circuit (3), and a second signal end (4b) of the input/output interface circuit (4) is used as a total output end (ID) and connected to an input end of the charger circuit or the discharge controller.
2. The protection circuit of a variable voltage lithium battery pack according to claim 1, wherein: the bidirectional isolation circuit (8) comprises a first optical coupler (U3), a second optical coupler (U4), a first resistor (R1) and a second resistor (R2), the first communication end (31) comprises a first output communication end (311) and a first input communication end (312), and the third communication end (71) comprises a third output communication end (712) and a third input communication end (711);
the anode of a light emitting diode of the first optocoupler (U3) is connected with a first output communication end (311), the cathode of the light emitting diode of the first optocoupler (U3) is connected with the cathode of the first battery pack (1) through a first resistor (R1), the collector of a triode of the first optocoupler (U3) is connected with a third input communication end (711), and the emitter of the triode of the first optocoupler (U3) is connected with the cathode of the second battery pack (5);
the positive electrode of a light emitting diode of the second optical coupler (U4) is connected with the third output communication end (712), the negative electrode of the light emitting diode of the second optical coupler (U4) is connected with the negative electrode of the second battery pack (5) through a second resistor (R2), the collector electrode of a triode of the second optical coupler (U4) is connected with the first input communication end (312), and the emitter electrode of the triode of the second optical coupler (U4) is connected with the negative electrode of the first battery pack (1).
3. The protection circuit of a variable voltage lithium battery pack according to claim 1, wherein: the first signal detection processing circuit (3) and the second signal detection processing circuit (7) are integrated circuits with the models of BigSur6 respectively.
4. A protection circuit of a variable voltage lithium battery pack comprises
A first battery pack (1) comprising at least two lithium batteries connected in series with each other;
the first RC filter (2) comprises a plurality of RC filter circuits which are correspondingly connected in series with each lithium battery in the first battery pack (1);
the first signal detection processing circuit (3) comprises a plurality of detection signal input ends and at least one communication end, wherein the output end of each RC filter circuit in the first RC filter (2) is connected to the detection signal input end corresponding to the first signal detection processing circuit (3);
a second battery pack (5) comprising at least two lithium batteries connected in series with each other;
the second RC filter (6) comprises a plurality of RC filter circuits which are correspondingly connected with each lithium battery in the second battery pack (5) in series;
a second signal detection processing circuit (7) comprising a plurality of detection signal input terminals and at least one communication terminal, wherein the output terminal of each RC filter circuit in the second RC filter (6) is connected to the corresponding detection signal input terminal of the second signal detection processing circuit (7);
the method is characterized in that: the protection circuit also comprises
The bidirectional isolation circuit (8) can realize bidirectional communication and signal isolation between the first signal detection processing circuit (3) and the second signal detection processing circuit (7), and the bidirectional isolation circuit (8) comprises a first signal transmission terminal (81) and a second signal transmission terminal (82);
the input/output interface circuit (4) comprises a first signal end (4a) and a second signal end (4b) which can realize bidirectional communication, and the input/output interface circuit (4) is used for realizing signal transmission between the battery pack and the charger and between the battery pack and the discharge controller;
the first power switch circuit (41) and the second power switch circuit (42) are used for controlling the on-off of an external load circuit when the first battery pack (1) and the second battery pack (5) are in different series-parallel connection states;
a free-wheeling circuit (43) providing a current loop for the back electromotive force generated by the inductive load at the moment when the power switch circuit is turned off;
the series-parallel detection circuit (9) is used for detecting the series-parallel working state of the external load on the protection circuit;
a load detection circuit (44) for detecting whether an external load is connected to the protection circuit and sending a trigger signal to the first signal detection processing circuit (3);
the first signal detection processing circuit (3) comprises a first communication end (31), a second communication end (32), a third communication end (33), a fourth communication end (34) and a fifth communication end (35), and the second signal detection processing circuit (7) comprises a sixth communication end (71) and a seventh communication end (72);
a first signal end (4a) of the input/output interface circuit (4) is connected with a fifth communication end (35) of the first signal detection processing circuit (3), and a second signal end (4b) of the input/output interface circuit (4) is used as a total output end (ID) and is connected to the input end of the charger circuit or the discharge controller;
a first signal transmission terminal (81) of the bidirectional isolation circuit (8) is connected with a first communication terminal (31) of the first signal detection processing circuit (3), and a second signal transmission terminal (82) of the bidirectional isolation circuit (8) is connected with a sixth communication terminal (71) of the second signal detection processing circuit (7);
the second communication end (32) of the first signal detection processing circuit (3) is connected with the series-parallel connection detection circuit (9); the third communication terminal (33) of the first signal detection processing circuit (3) is connected with the input terminal of a first power switch circuit (41), the output terminal of the first power switch circuit (41) is used as a first negative electrode discharge output terminal (P1-) of the whole protection circuit, and the positive electrode of the first battery pack (1) is used as a first positive electrode discharge output terminal (P1+) of the whole protection circuit; the fourth communication terminal (34) of the first signal detection processing circuit (3) is connected with the output terminal of the load detection circuit (44), and the input terminal of the load detection circuit (44) is connected with the first negative electrode discharge output terminal (P1-);
a seventh communication terminal (72) of the second signal detection processing circuit (7) is connected with an input terminal of a second power switch circuit (42), an output terminal of the second power switch circuit (42) is used as a second negative electrode discharge output terminal (P2-) of the whole protection circuit, and an anode of the second battery pack (5) is used as a second positive electrode discharge output terminal (P2+) of the whole protection circuit;
the follow current circuit (43) is connected between the second positive electrode discharging output end (P2+) and the first negative electrode discharging output end (P1-) in series.
5. The protection circuit of a variable voltage lithium battery pack according to claim 4, wherein: the bidirectional isolation circuit (8) comprises a first optical coupler (U3), a second optical coupler (U4), a first resistor (R1) and a second resistor (R2), the first communication end (31) comprises a first output communication end (311) and a first input communication end (312), and the sixth communication end (71) comprises a sixth input communication end (711) and a sixth output communication end (712);
the anode of a light emitting diode of the first optocoupler (U3) is connected with a first output communication end (311), the cathode of the light emitting diode of the first optocoupler (U3) is connected with the cathode of the first battery pack (1) through a first resistor (R1), the collector of a triode of the first optocoupler (U3) is connected with a sixth input communication end (711), and the emitter of the triode of the first optocoupler (U3) is connected with the cathode of the second battery pack (5);
the positive electrode of a light emitting diode of the second optical coupler (U4) is connected with the sixth output communication end (712), the negative electrode of the light emitting diode of the second optical coupler (U4) is connected with the negative electrode of the second battery pack (5) through a second resistor (R2), the collector electrode of a triode of the second optical coupler (U4) is connected with the first input communication end (312), and the emitter electrode of the triode of the second optical coupler (U4) is connected with the negative electrode of the first battery pack (1).
6. The protection circuit of a variable voltage lithium battery pack according to claim 4, wherein: the first signal detection processing circuit (3) and the second signal detection processing circuit (7) are integrated circuits with the models of BigSur6 respectively.
7. The protection circuit of a variable voltage lithium battery pack according to claim 4, wherein: the follow current circuit (43) comprises a follow current diode (Dx), the anode of the follow current diode (Dx) is connected with the first cathode discharge output end (P1-), and the cathode of the follow current diode (Dx) is connected with the second anode discharge output end (P2 +).
8. The protection circuit of a variable voltage lithium battery pack according to claim 4, wherein: the series-parallel detection circuit (9) comprises a digital triode (Q3), the collector of the digital triode (Q3) is connected with the second communication end (32) of the first signal detection processing circuit (3), the emitter of the digital triode (Q3) is connected with the negative electrode of the first battery pack (1), and the base of the digital triode (Q3) is connected with the negative electrode of the second battery pack (5).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021235351.8U CN212343374U (en) | 2020-06-29 | 2020-06-29 | Protection circuit of variable voltage lithium cell group |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021235351.8U CN212343374U (en) | 2020-06-29 | 2020-06-29 | Protection circuit of variable voltage lithium cell group |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212343374U true CN212343374U (en) | 2021-01-12 |
Family
ID=74076884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021235351.8U Active CN212343374U (en) | 2020-06-29 | 2020-06-29 | Protection circuit of variable voltage lithium cell group |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212343374U (en) |
-
2020
- 2020-06-29 CN CN202021235351.8U patent/CN212343374U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN201639290U (en) | Device for preventing main loop of backup battery from being inversely connected | |
| CN209389733U (en) | Lithium battery protection board | |
| WO2020181437A1 (en) | Cell protection circuit and electronic device | |
| CN102136750B (en) | Monomer charging and discharging tail balancing module and battery pack balancing protection management system thereof | |
| CN113544007A (en) | Control circuit, battery management system and electrochemical device | |
| CN212304824U (en) | Novel positive charging activation circuit of BMS accuse | |
| CN109638904A (en) | Lithium battery protection board | |
| CN103066648A (en) | Battery driving equalization circuit | |
| CN211790810U (en) | Charging system, charger, battery pack and movable platform | |
| CN219843450U (en) | Charging and discharging control circuit, power supply circuit and energy storage device | |
| CN210839035U (en) | Energy storage power supply | |
| CN212343374U (en) | Protection circuit of variable voltage lithium cell group | |
| CN215009658U (en) | Battery protection circuit and rechargeable battery | |
| CN111682621A (en) | Protection circuit of variable voltage lithium cell group | |
| CN202121334U (en) | Monocase charge-discharge end supplement equalization module and battery set equalization protection management system thereof | |
| CN111446746B (en) | Over-discharge protection and recovery circuit of rechargeable battery | |
| CN104143663A (en) | High-current lithium ion battery pack with self-protective function and expansibility | |
| CN216774339U (en) | Battery management circuit | |
| CN210985720U (en) | Mixed type battery pack charging and discharging control system | |
| CN114243813B (en) | Lithium battery pack voltage stabilizing and balancing control system and method | |
| CN219204128U (en) | Charging system based on intelligent lithium battery BMS protection board | |
| CN216390559U (en) | Battery management circuit and energy storage system | |
| CN219513815U (en) | Charger circuit | |
| CN116247781B (en) | Low-power consumption power supply circuit of high-voltage lithium battery BMS | |
| CN209344812U (en) | A kind of battery protecting circuit and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |